mirror of https://gitee.com/openkylin/linux.git
124 lines
3.3 KiB
C
124 lines
3.3 KiB
C
/*
|
|
* linux/fs/9p/vfs_dentry.c
|
|
*
|
|
* This file contians vfs dentry ops for the 9P2000 protocol.
|
|
*
|
|
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
|
|
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to:
|
|
* Free Software Foundation
|
|
* 51 Franklin Street, Fifth Floor
|
|
* Boston, MA 02111-1301 USA
|
|
*
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/file.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/stat.h>
|
|
#include <linux/string.h>
|
|
#include <linux/smp_lock.h>
|
|
#include <linux/inet.h>
|
|
#include <linux/namei.h>
|
|
#include <linux/idr.h>
|
|
|
|
#include "debug.h"
|
|
#include "v9fs.h"
|
|
#include "9p.h"
|
|
#include "v9fs_vfs.h"
|
|
#include "fid.h"
|
|
|
|
/**
|
|
* v9fs_dentry_validate - VFS dcache hook to validate cache
|
|
* @dentry: dentry that is being validated
|
|
* @nd: path data
|
|
*
|
|
* dcache really shouldn't be used for 9P2000 as at all due to
|
|
* potential attached semantics to directory traversal (walk).
|
|
*
|
|
* FUTURE: look into how to use dcache to allow multi-stage
|
|
* walks in Plan 9 & potential for better dcache operation which
|
|
* would remain valid for Plan 9 semantics. Older versions
|
|
* had validation via stat for those interested. However, since
|
|
* stat has the same approximate overhead as walk there really
|
|
* is no difference. The only improvement would be from a
|
|
* time-decay cache like NFS has and that undermines the
|
|
* synchronous nature of 9P2000.
|
|
*
|
|
*/
|
|
|
|
static int v9fs_dentry_validate(struct dentry *dentry, struct nameidata *nd)
|
|
{
|
|
struct dentry *dc = current->fs->pwd;
|
|
|
|
dprintk(DEBUG_VFS, "dentry: %s (%p)\n", dentry->d_iname, dentry);
|
|
if (v9fs_fid_lookup(dentry)) {
|
|
dprintk(DEBUG_VFS, "VALID\n");
|
|
return 1;
|
|
}
|
|
|
|
while (dc != NULL) {
|
|
if (dc == dentry) {
|
|
dprintk(DEBUG_VFS, "VALID\n");
|
|
return 1;
|
|
}
|
|
if (dc == dc->d_parent)
|
|
break;
|
|
|
|
dc = dc->d_parent;
|
|
}
|
|
|
|
dprintk(DEBUG_VFS, "INVALID\n");
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* v9fs_dentry_release - called when dentry is going to be freed
|
|
* @dentry: dentry that is being release
|
|
*
|
|
*/
|
|
|
|
void v9fs_dentry_release(struct dentry *dentry)
|
|
{
|
|
int err;
|
|
|
|
dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
|
|
|
|
if (dentry->d_fsdata != NULL) {
|
|
struct list_head *fid_list = dentry->d_fsdata;
|
|
struct v9fs_fid *temp = NULL;
|
|
struct v9fs_fid *current_fid = NULL;
|
|
|
|
list_for_each_entry_safe(current_fid, temp, fid_list, list) {
|
|
err = v9fs_t_clunk(current_fid->v9ses, current_fid->fid);
|
|
|
|
if (err < 0)
|
|
dprintk(DEBUG_ERROR, "clunk failed: %d name %s\n",
|
|
err, dentry->d_iname);
|
|
|
|
v9fs_fid_destroy(current_fid);
|
|
}
|
|
|
|
kfree(dentry->d_fsdata); /* free the list_head */
|
|
}
|
|
}
|
|
|
|
struct dentry_operations v9fs_dentry_operations = {
|
|
.d_revalidate = v9fs_dentry_validate,
|
|
.d_release = v9fs_dentry_release,
|
|
};
|